Computer algebra system (CAS) in Python. SymPy is a Python library for symbolic mathematics. It aims to become a full-featured computer algebra system (CAS) while keeping the code as simple as possible in order to be comprehensible and easily extensible. SymPy is written entirely in Python and does not require any external libraries. This package contains the interactive shell for SymPy, i.e., isympy, which starts ipython/python interactive shell and loads SymPy.